public class Main {
    public static void main(String[] args) {
        MySingleList singleList = new MySingleList();
        singleList.addFirst(12);
        singleList.addLast(23);
        singleList.addLast(34);
        singleList.addIndex(3, 56);
        singleList.display();
        singleList.delNode(0);
        singleList.display();
    }
}